he plant expression vector pROK II containing antisense ribozyme gene of rice dwarf virus(RDV)S5 was transferred to rice immature embryo by microprojectile bombardrnent.The resis-tant calli were obtained in the presence of G418. Two or three months later these calli could differ-entiate to shoot after transferred to differential medium. The transformation of the regeneratedrice plant was confirmed by Southern blot.Transgenic plants were inocuiated with viruliferous leafhopper(Nephotettix cincticeps)to determine their RDV resistance.The results showed thatthe infection of RDV was not prevented but the symptoms were milder than control.Most of thetransgenic rice plants were fertile while the control was not.In order to assay the RDV replica-tion,virus concentration was detected by ELISA. The results indicated that the repliea.tion of RDVin transgenic plants was obviously inhibited.